Screw-propeller



A, P. BL1VBN.

SCREW PROPBLLBR Patented Ja,11.30,1183.

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TTORNEY ALONZO P. BLIVEN, OF BROOKLYN,

PATENT OFFICE.

N. Y., ASSIGNOR TO THE AMERICAN QUICK TRANSIT STEAMSHIP COMPANY, OF BOSTON, MASSACHUSETTS. A

SCREW-PROPELLER.

SPECIFICATION forming part of Letters Patent No. 271,-Sl12, dated January 30, 1.853.

Application filed February 15, 1882. (No model.)

To all whom it may concern 4 Be it known that I, ALONZO P. BLIVEN, a citizen ofthe United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain Improvements in Screw-Propulsion, of which the following is a specication.

The said invention relates to the propulsion of vessels by screw-propellers in such a manner that the parts of a broken screw may he effectively rearranged, and in the event of its loss or destruction recourse may be had to a supplementary screw, and dependence upon sails avoided, thus dispensing with spars and other top-hamper, from which the chief benet to a fast steamer, in compensation forits ordinary retarding effect, is only realized in thecase of accident to the propelling machinery. The blades of the propeller are made separately and fitted around the shaft in such a way that those of a four-bladed propeller, if one blade should be broken, may be arranged to serve efficiently as a three-bladed screw, and in the event of its loss or destruction the power may be applied through the supplementary propeller that is independent of the machineryT and propeller that ordinarily drive the vessel.

Figure l of the drawings annexed represents the side view of the stern of a vessel 'tted with a large screw, and with a smaller one placed above the main shaft, where it will not interferewith the dow of the water to the main screw. The small propeller is a two-bladed screw placed forward of the stern-post in the dead-wood of the ship, in which it may be in closed when the blades are in a vertical position by shutters that are hinged on the after edge to the hull like a rudder, and in such a manner that they maybe worked from the inside and turned and held back out of the way of the revolutions ofthe screws. Each of the shutters is provided like a rudder with a head, a., and a tiller, b, by which it may be handled and secured to leave the screw-openings free,-

and also to enable it to be used in connection with that on the opposite side of the stern to steer the vessel. They may also be used effectlvely as' drags. This supplementary screw may be operated by separate boilers and machinery that may be otherwise employed for hoisting and other ordinary purposes, and it nia-y be applied to sailing-vessels that it is desirable to supply with auxiliary propelling power to be used on special occasions.

Fig. 2 is a front view of the main propeller on an enlarged scale, which is represented with four blades, although the same method of construction is applicable to a screw with any `number of blades. The dotted lines show the change in position of twoof the blades, if the one between them should be broken, so that the remaining three blades will be disposed at equal distances' around the circle.

Fig. 3 represents longitudinal and transverse sections of the hub that fits upon the end of the shaft and shows how the parts are placed and held together. The blades are each made with two tenons on the hub-sections that fit into corresponding mortises on the shaft, and they are held in position by the bands c, that are fastened over the hubs on each side of the screw. Forward of the screw there is a collar on the shaft, that takes with the tenons the thrust from each blade of the screw, and on the after side is a washer that is held securely against the hub and. the band on that side by a bolt tapped into the end of the shaft. Bythis method of constructing and combining the parts the blades may be forged or cast separately and held securely together. The sections of the hub that are shown in the drawings extend around the shaft to form a complete hub ybut it is obvious that they may be made smaller and the intervening spaces blocked up or fitted with keys, as they would be if oneof the blades were taken out, and that the parts in my arrangement are held in their proper positions by the inclosing bands.

A vessel .like that shown in the drawings is intended to be propelled chiefly by vthe main screw, and in the event of accident to one of its blades the others may be rearranged with uniformity; and if it should be entirely lost or disabled, the supplementary propeller may be used in its place without recourse to spars and other top-hamper, that may therefore be wholly dispensed with. In the meanwhile, and under. ordinary circumstances, the auxiliary screw with its inclosing shuttersv presents no obstruction to the ow of the water along the run of the vessel.

I claim as my invention and desire to secure by Letters Patentl. The combination of an auxiliary propel- IDO 1er in the deed-wood of a. ship forward of the by the bands c,substantia1lyin the'manner destern-posb, above the main shaft, and inclosed scribed. with hinged sh utters that may be Worked from the insde,substantially in the manner and for ALONZO P' BLYVEN the purpose described. v Witnesses: 2. The construction of a screw-propeller with GRAS. E. LANSING,

separate blades tenoned into the shaft and heid WM. KEMBLE HALL. 

